The blinds are the forced bets in almost all poker variants. This bets have to be paid from two players before the cards are dealt. The players who have to bet this blinds change from round to round. There exist one big blind and one small blind. The small blind is the half of the big blind.
The position of the dealer determines who pays the blinds. The two players immediately to the left of the dealer pay the blinds. At a cash game table the blinds stay all the time the same. At poker tournaments and sit&go games, the blinds increase every 3-10 minutes.